When you purchase the wired doorbell and hardwire it with your existing doorbell wires, you may find that your existing chime begins buzzing. How could that happen? 

In this case, please make sure you have used the jumper to bypass the existing wires. You can find it in the package content. Use the provided jumper for the existing chime to connect the two terminals. This is to bypass the doorbell chime and will not affect the normal operation of the circuit. 

Without this step, the video doorbell will still be able to power on but will operate unstably. When the jumper is in place, the existing chime will not sound anymore.